﻿// <com.woyouqiu.Copyright>
// --------------------------------------------------------------
// <copyright>上海有求网络科技有限公司 2015</copyright>
// <Solution>MyCompany.MyProject</Solution>
// <Project>MyCompany.MyProject.Application</Project>
// <FileName>CoordinateTransform.cs</FileName>
// <CreateTime>2017-04-23 17:56</CreateTime>
// <Author>何苗</Author>
// <Email>hemiao@woyouqiu.com</Email>
// <log date="2017-04-23 17:56" version="00001">创建</log>
// --------------------------------------------------------------
// </com.woyouqiu.Copyright>

using System;
using Vecen.BangChuang.BangChuang.Areas.Dtos;

namespace Vecen.BangChuang.BangChuang.Areas {
    /**
  * 各地图API坐标系统比较与转换;
  * WGS84坐标系：即地球坐标系，国际上通用的坐标系。设备一般包含GPS芯片或者北斗芯片获取的经纬度为WGS84地理坐标系,
  * 谷歌地图采用的是WGS84地理坐标系（中国范围除外）;
  * GCJ02坐标系：即火星坐标系，是由中国国家测绘局制订的地理信息系统的坐标系统。由WGS84坐标系经加密后的坐标系。
  * 谷歌中国地图和搜搜中国地图采用的是GCJ02地理坐标系; BD09坐标系：即百度坐标系，GCJ02坐标系经加密后的坐标系;
  * 搜狗坐标系、图吧坐标系等，估计也是在GCJ02基础上加密而成的。 chenhua
  */
    public class CoordinateTransform {

        private const string BAIDU_LBS_TYPE = "bd09ll";

        private static double pi = 3.1415926535897932384626;
        private static double a = 6378245.0;
        private static double ee = 0.00669342162296594323;

        /**
         * 84 to 火星坐标系 (GCJ-02) World Geodetic System ==> Mars Geodetic System
         * 
         * @param lat
         * @param lon
         * @return
         */
        public Coordinate Gps84_To_Gcj02(double lat, double lon) {
            if(OutOfChina(lat, lon)) {
                return null;
            }
            double dLat = TransformLat(lon - 105.0, lat - 35.0);
            double dLon = TransformLon(lon - 105.0, lat - 35.0);
            double radLat = lat / 180.0 * pi;
            double magic = Math.Sin(radLat);
            magic = 1 - ee * magic * magic;
            double sqrtMagic = Math.Sqrt(magic);
            dLat = (dLat * 180.0) / ((a * (1 - ee)) / (magic * sqrtMagic) * pi);
            dLon = (dLon * 180.0) / (a / sqrtMagic * Math.Cos(radLat) * pi);
            double mgLat = lat + dLat;
            double mgLon = lon + dLon;
            return new Coordinate(mgLat, mgLon, CoordinateSystem.GCJ_02);
        }

        /**
         * * 火星坐标系 (GCJ-02) to 84 * * @param lon * @param lat * @return
         * */
        public Coordinate Gcj_To_Gps84(double lat, double lon) {
            double lontitude;
            double latitude;
            if(OutOfChina(lat, lon)) {
                lontitude = lon * 2 - lon;
                latitude = lat * 2 - lat;
            } else {
                double dLat = TransformLat(lon - 105.0, lat - 35.0);
                double dLon = TransformLon(lon - 105.0, lat - 35.0);
                double radLat = lat / 180.0 * pi;
                double magic = Math.Sin(radLat);
                magic = 1 - ee * magic * magic;
                double sqrtMagic = Math.Sqrt(magic);
                dLat = (dLat * 180.0) / ((a * (1 - ee)) / (magic * sqrtMagic) * pi);
                dLon = (dLon * 180.0) / (a / sqrtMagic * Math.Cos(radLat) * pi);
                latitude = lat + dLat;
                lontitude = lon + dLon;
            }

            return new Coordinate(latitude, lontitude, CoordinateSystem.WGS84);
        }

        /**
         * 火星坐标系 (GCJ-02) 与百度坐标系 (BD-09) 的转换算法 将 GCJ-02 坐标转换成 BD-09 坐标
         * 
         * @param gg_lat
         * @param gg_lon
         */
        public Coordinate Gcj02_To_Bd09(double gg_lat, double gg_lon) {
            double x = gg_lon, y = gg_lat;
            double z = Math.Sqrt(x * x + y * y) + 0.00002 * Math.Sin(y * pi);
            double theta = Math.Atan2(y, x) + 0.000003 * Math.Cos(x * pi);
            double bd_lon = z * Math.Cos(theta) + 0.0065;
            double bd_lat = z * Math.Sin(theta) + 0.006;
            return new Coordinate(bd_lat, bd_lon, CoordinateSystem.BD_09);
        }

        /**
         * * 火星坐标系 (GCJ-02) 与百度坐标系 (BD-09) 的转换算法 * * 将 BD-09 坐标转换成GCJ-02 坐标 * * @param
         * bd_lat * @param bd_lon * @return
         */
        public Coordinate Bd09_To_Gcj02(double bd_lat, double bd_lon) {
            double x = bd_lon - 0.0065, y = bd_lat - 0.006;
            double z = Math.Sqrt(x * x + y * y) - 0.00002 * Math.Sin(y * pi);
            double theta = Math.Atan2(y, x) - 0.000003 * Math.Cos(x * pi);
            double gg_lon = z * Math.Cos(theta);
            double gg_lat = z * Math.Sin(theta);
            return new Coordinate(gg_lat, gg_lon, CoordinateSystem.GCJ_02);
        }

        /**
         * (BD-09)-->84
         * @param bd_lat
         * @param bd_lon
         * @return
         */
        public Coordinate Bd09_To_Gps84(double bd_lat, double bd_lon) {

            Coordinate gcj02 = Bd09_To_Gcj02(bd_lat, bd_lon);
            Coordinate map84 = Gcj_To_Gps84(gcj02.Latitude, gcj02.Longitude);
            return map84;
        }

        /// <summary>
        /// 是否出了中国
        /// </summary>
        /// <param name="lat"></param>
        /// <param name="lon"></param>
        /// <returns></returns>
        public bool OutOfChina(double lat, double lon) {
            if(lon < 72.004 || lon > 137.8347)
                return true;
            if(lat < 0.8293 || lat > 55.8271)
                return true;
            return false;
        }
        /// <summary>
        /// 
        /// </summary>
        /// <param name="x"></param>
        /// <param name="y"></param>
        /// <returns></returns>
        private double TransformLat(double x, double y) {
            double ret = -100.0 + 2.0 * x + 3.0 * y + 0.2 * y * y + 0.1 * x * y + 0.2 * Math.Sqrt(Math.Abs(x));
            ret += (20.0 * Math.Sin(6.0 * x * pi) + 20.0 * Math.Sin(2.0 * x * pi)) * 2.0 / 3.0;
            ret += (20.0 * Math.Sin(y * pi) + 40.0 * Math.Sin(y / 3.0 * pi)) * 2.0 / 3.0;
            ret += (160.0 * Math.Sin(y / 12.0 * pi) + 320 * Math.Sin(y * pi / 30.0)) * 2.0 / 3.0;
            return ret;
        }

        /// <summary>
        /// 
        /// </summary>
        /// <param name="x"></param>
        /// <param name="y"></param>
        /// <returns></returns>
        private double TransformLon(double x, double y) {
            double ret = 300.0 + x + 2.0 * y + 0.1 * x * x + 0.1 * x * y + 0.1 * Math.Sqrt(Math.Abs(x));
            ret += (20.0 * Math.Sin(6.0 * x * pi) + 20.0 * Math.Sin(2.0 * x * pi)) * 2.0 / 3.0;
            ret += (20.0 * Math.Sin(x * pi) + 40.0 * Math.Sin(x / 3.0 * pi)) * 2.0 / 3.0;
            ret += (150.0 * Math.Sin(x / 12.0 * pi) + 300.0 * Math.Sin(x / 30.0 * pi)) * 2.0 / 3.0;
            return ret;
        }
    }
}